Hypervelocity gun



Aprnl 21, 1959 A. B. J. CLARK -ET AL 2,832,795

HYPERVELOCITY GUN Filed Feb. 15, 1957 2 SheetsSheet 2 INVENTR5 AUSTIN B. J. CLRK PAUL T. BOLTZ W ATTORNYD U Stas Patent HYPERVELOCIIY GUN Austin B. J Clark, Oxon Hi, and Paul T. Boltz, Potomac Heights, Mdr

The invention described herein may be manufactured and used by or for the Government of the United States of America for 'govemmental prirposes without the payment of any royalties thereon or theretor.

The present invention relates to high-velocity guns and more particularly to a cylinder which forms a compres sien chamber and piston (energy absorber for a hyperi\elocity gun.

High velocity guns prsently knowh in the art are unsatisfatoryfor one reason or another. Some guns have compression chambers with the projectile to be accelerated mounted at one end of the chamber, air is pumped into the chamber at high pressure until the projectile is sheared from its mountings and thus forced from the chamber. Such deviees require bulk and expensive equipment to provide the necessary pressures at which the projectiles are sheared and the desired high velocities cannot be obtained by this method. Other high-velocity guns make use of a compression chamber in which a proectile is secured at one end and a piston is forced into the chamber from the other end to compress air therein wheteupon the compressed air forces the projectile from the gun. In this type of gun, the gun barrel is damaged by the piston when the piston expends its kinetic energy -by hitting the end of the gun barrel atter forcing the projectile therefrom. This requires rcplacng the gun barrels regularly and also requires new pistons.

Heretofore even the most complicated and expensive systems have been unable to attain an adequately high velocity.

The present invention overcomes the above short comings and provides an effective, inexpensive high-velocity gun which can be fired continuously without damage to the gun barre]. This is done by providing a compression chamber of a particular design which absorbs the energy of the piston before the piston reaches the gun barrel and yet permits the piston to compress the gas to maximum over the full distance of the compression chamber.

An object of the present invention is to provide a hypervelocity gun which can be fired without damage to the barrel of the gun.

Another object is to provide a compression chamber for a hypervelocity gun which will absorb the energy of the piston without damage to the gun.

Still another object is to provide a hypervelocit gun which can be operated inexpensively and yet impart a high velocity to a shear projectile,

Yet another object is to provide a gun for producing high velocity particles, for their study and effects on impact.

'The exact nature of this invention as.well as other objects and advantages thereof will be readily apparent from consideration of the following specification relating to the annexed drawings in which: V

Fig. 1 is a diagrammafic side elevation view of a hypervlocity gun illustrating the relative parts according to this invention;

Fig. 2 is a sectional view of the connector and com- {pression chamber showing the arrangement of the shearprojectile in the projectile holder, and a piston traveling down the barrel;

Fig. 3 illustrates partly in section, a standard 50 caliber casing cut away to show the end of a pistonsecured in the end thereof;

Fig. 4 is a sectional view of a valve for supplying a gas to the compression chamber illustrating the parts in more detail; and

Fig. 5 illustrates a gas line connection between the valve and the gun barre].

In accordance with the present invention, a hypervelocity gun is provided for imparting high velocity to a shear-projectile. A preferred embodiment comprises a standard gun of a predetermined caliber to which a barrel extension of a smaller predetermined caliber has been secured by a connector. A cylinder forming a compression chamber having at one end au inner diameter equal to the inner diameter of the larger caliber barrel With the opposite end tapering to an inner diameter equal to the smaller caliber gun barrel and a shear-projectile holder is coaxially disp-osed within the connector and firmly held in gas tight linear alignment between the gun barrels. The bullet ordinarily fired from the cartridge of the standard gun is replaced by a piston of the same caliber. Helium or any preferred gas is introduced under pressure into the larger caliber gun barre]. The piston is fired and moves down the gun barrel into the compression chamber, pressure is built up by the piston comprising the helium gas and when the pressure is great enough the projectile shears out and is accelerated by the gas'pressure. The piston finally enters the tapered part of the cylinder causing plastic flow in either the cylinder, the piston, or both, thus dissipating the kinetic energy of the piston without damaging either gun barrel. The cylinder forming the compression chamber, the piston, and the projectile holder are expendable and can be replaced after each firing or when necessary.

High-velocity guns according to this invention impart velocities of 10,000 to 15,000 ft./sec. to shear projectiles which enables a study of the penetrafion of small particles traveling around 24,000 ft./sec. or more madeby secondary fragments in the splash produced by the impact of a projectile traveling about 12,000 ft./sec. The

velocities of secondary fragments produced by impact of a projectile may be as much as five times as fast as the V projectile velocity. These very high secondary velocities permit studies of the possible efiect of meteor particles on missiles traveling in outer space and the effect of high velocity particles on impact With difierent materials or for any desired study.

Referring now to the drawings and more particularly to Fig. 1, a diagrammatic illustration of a hypervelocty gun 10 according to the present invention isrshown in operative arrangement which comprises a 50 caliber gun 11, a 30 caliber gun barrel extension 12 connected to the end of the 50 caliber barrel 13 by a cylindrical connector 14, and a vacuum test chamber 19 connected to the end of the 30 caliber gun barrel. A valve 17 is shown connected to the 50 caliber barrel and to a supply tank 18 of a gas such as helium or hydrogen for the purpose of introducing gas into the 50 caliber gun barrel and the compression chamber.

Fig. 2 is a detailed view of the connector 14 illustrafing an inner cylinder 15, and a shear projectile holder 16 positioned coaxially with the connector in operative relationship between the gun barrels. As shown, the gun barrels are threaded on the respective ends thereof and the connector 14 is threaded on the inner diameter of each end thereof for receiving the threaded ends of the Patented Apr. 21, 1959 barrels 12 and 13. The cylinder 15 forms a pressure chamber which is in alignmemt With the gun barrels to form an extension for the 50 caliber barrel and has an inner diameter at one end equal to. the diameter-ofthe adjacent.50 caliber.gun barrel. whereas the.inner diameter. of,the opposite end tapers over the last one half inch to.

holder in a gas tight assembly between the gun barrels. The. connecter is provided With ridges 21 on the inner surface to hold the compression chamber in coaxial relationship and to.provide a space betweenthe compression chamber.and the coupling to allow for expansion of the compression chamber during firing.

Fig. 2 further illustrates a shear.projectile 22 positioned in the projectile holder, and a piston 23 in the 50 caliber barrel. Each, the piston and the shear projectile, has ring seals 20 around the surface thereof to prevent gas from bypassing. The shear projectile can be made of any preferred material and weight depending on the purpose of.use thereof. For example, a shear projectile made of 248 aluminum and weighing 1% grams will. obtain a velocityof about 10,000 ft./ sec. when fired fromthe high velocity gun of this invention.

Fig. 3 illustrates a standard 50 caliber casing 24 shown.

in combination with a piston 23 whichis designed to replace the standard 50 caliber projectile. The piston has approximately the same diameter as the gun barrel and. has 0 rings thereon in order to prevent gas from escaping by the piston in order to compress the gas as much as possible.

Fig. 4 is a detailed view in cross section of the valve 17. The valve is a double acting type which comprises a body 25, an inlet 26, a bleeder outlet 27, an outlet 28 and appropriate passages between the inlet, the bleeder outlet and the outlet passage28. Needle valves 31.amd-

32 provide respectively control means for closing or opening the passage from the inlet or to the bleeder outlet as desired..

Fig. illustrates the connection between the gas lime and the 50 caliber gun barrel. In order to prevent weakening of the gun barrel at the connection a ring 33 is positioned around the barrel and a fitting secures the gas-lime to the ring such that the end of the lime connects with a passage 34 that has been bored into the barrel and connects with the bore therein. The entrance to the passage is tapered at 35 to receive the end of the.gas lime that has been shaped to provide a tight fit between the end of the lime and the tapered end 35 of the passage. The gas lime is secured in the ring by a gland nut 36 which. is threaded into a threaded hole 37 in the ring around the barrel and which fits over a sleeve 38 which is threaded onto the end of the gas line. When the gland nut is screwed intothe ring, shoulders on the inside thereof press against the sleeve 38 which forces the end of the gas lime into the tapered end portion of the passage through the gun barrel. The end portion of the gas lime fitting into the tapered end portion et passage 33 holds the ring in place about the barrel.

The same type of fitting is used to makelneconnectien with the valve 17 for securing thereto appropriate gas limes which are controlled by thevalve.

In assembling and operating the device a shear-projectile is positioned in the shear projectile holder, then.

the compression chamber and the projectile holder is assembledin gas tight relationship between the 50 and 30 caliber gun-barrels by tightening the connecter onto the 50 caliber barrel and the 30 caliber barrel as shown by illustration in Fig. 2. The piston 23 is assembledh the 50 caliber casing and then the cartridge is positioned in the breech ready for firing. In order to increase the transfer of energy from the piston to the shear projectile the area between the piston and the shear projectile is evacuated through the bleeder valve 27 to withdraw the air and then a gas undr pressuresuch as helium is introduced into the area through inlet valve 26. Thehypervelncity gun is now assembled and ready for ring.

When the cartridge is firedthe piston is driven down the 50 caliber barrel and into.the compression chamber, compressmg the helium gas or any other suitable gas until the projectile shearsfrom the projectile holder. Thepiston continues across the compression chamber and expends its energy by plasticall defcrming its'elf in the tapered end of the compression chamber and at the same time expanding the compression chamber and the projectile holder into the.space between the conmector and, the compression chamber provided for such expansion..

In this manner thepistomexpends its kinetic energy without damage to either gun barrel or the connecter. The

tapered end of the barrel extension provides a piston energyabsorber and also permits the end of the piston, on defozming, approximately to fill the entire area of thetapered end portion to.force all of the gas from behind the shear projectile holder thereby. making use,

of all the gas possible.

In the hypervelocit gun illustrated, the 50 caliber gun. has a barrel. of' 39 inches, and a 30 caliber gunbarrel:

of 38 inches in lemgth extemding therefrom with a cyl' imder 4 imches.in length forming the. gas compression chamber between the two barrels.

troduced at about 650 lbs/in. which constitutes about l/2' grams or 5 quarts at atmospheric pressure. The

pressure obtained in the pressure chamberby the fired piston before shearing the projectile is estimated to be 300,000 lbs/in? to provide a velocity of 10,000 t0 15,000 ft./sec. respectively to 21 1 /2 gram or /2 gram projectile, the velocitybeng measured in vacuum after leaving the u barrel.

T he cylindrical cylinder forming-the compression chamber, the shear projectileholderand the piston arc'made of a mickel-chromium molybdenum steel (4340) which comprises by percentage carbon 0.3 80.43, manganese 0.600.80, phosphorus 0.04, silicon 0.200.35, nickel 1.65-

of the projectile depends on theweight of the projectile and the .transferral of energy from the gas to the pro jectile.

Obviously: many modifications and variations. ofthe present invention are possible in the light of the above teachings. It is therefore to be understood that-withim thescope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. An adapter for converting standard gun barrels to form a hypervelocity gun which comprises a cylindricah conmector adapted at ome end to receive a first gun barrel of predetermimed caliber and adapted at the opposite and to receive a secondgun barrel having a predetermined size of lesser caliber than said first barrel, a cylirider coaxially,dsposed within said connecter, said cylinder having an inner diameter at one end equal "to the inner diameter of said first gun barrel and tapered toward the opposite end to an inner diameter equal to the diameter of said second gun barrel, said cylinder =ab sorbimg all excess energy of a piston fired from said first gun barrel into said cylinder.

2. An adapter as claimed in claim 1, in which thta- The helium is inpered portion of the inner diameter of said cylinder is less than half the length of said cylinder from the end of said cylinder closer to said second gun barre].

3. An adapter as claimed in claim 1 in which the connecter has a spacer on the inner diameter thereof for centering said cylinder in coaxial alignment with said connecter.

4. An adapter for forming a high compression chamber and piston absorber for a hypervelocity gun which comprises a cylindrical connecter threaded on the inner diameter at one end thereof to receive a first threaded gun barrel of predetermined caliber and threaded on the opposite end to receive a second threaded gun barrel having a predetermined size of lesser caliber than said first gun barrel, a cylinder and a shear projectile holder coaxially disposed within said connector, said cylinder having an inner diameter at one end that extends along the greater length thereof equal to the inner diameter of said first gun barrel and tapered at the opposite end to an inner diameter at the end thereof which is equal to the diamcter of said second gun barrel, said shear projectile holder adapted to be positioned between said cylinder and said second gun barrel and having the same enter diameter as said cylinder with the same inner diameter as said second gun barrel, said cylinder absorbing all excess energy 01: a piston fired from said first gun barrel into said cylinder.

5. A hypervelocity gun for imparting high velocity to a shear projectile which comprises in combination a cylindrical connector threaded at one end to receive a first gun barrel of a predetermined caliber and threaded at the opposite end to receive a second gun barrel of predetermined caliber which is smaller than the caliber of said first gun barrel, a cylinder coaxially disposed within said connecter and positioned linearly between said gun barrels to form a compression chamber, said cylinder having an inner diameter at one end equal to the inner diameter of said first barrel and a taper at the opposite end to form an inner dameter at the tapered end thereof equal to the inner diameter of said second gun barrel, a shear projectile holder coaxiafly disposed within said connector and posifioned linearly between said cylinder and said second gun barrel, said projectile holder having the same outer diameter as said cylinder and the same inner diameter as said second gun barrel, and means adapted to said first gun barrel for firing a piston therein, said cylinder absorbing all excess energy of a piston fired from said first gun barre] into said cylinder.

6. A hypervelocity gun for imparting high velocity to a shear projectile which comprises, a first gun barrel of predetermined caliber, a second gun barrel of a smaller predetermined caliber than said first gun barre], a connector threaded on its inner diameter at one end to receive an end of said first gun barrel and threaded on the opposite end to receive said second gun barrel, a cylinder and a projectile holder coaxially disposed within said connecter and positioned linearly between said gun barrels, said cylinder forming a compression chamber having at one end a diameter equal to the inner diameter of said first gun barrel and extended substantially along the whole length thereof, the opposite end of said compression chamber tapering toward said second barrel to a diameter equal to the inner diameter of said second barrel, said projectile holder having the same outer diameter as said cylinder and the same inner diameter as said second barrel, said shear projectile adapted to be positioned in said projectile holder between said cylinder and said second barrel, and a piston adapted to be fired from said first gun barrel into said compression chamber whereby the excess kinetic energy of said piston is absorbed by the tapered end of said compression chamber.

7. A hypervelocity gun as claimed in claim 6, wherein said first barrel has a passage bored through the barrel and a valve means connected thereto for the introduction of a gas into the barrel and said compression chamber.

References Cited in the file of this patent UNITED STATES PATENTS 1,183,644 Hill May 16, 1916 1,314,801 Hanzlik Sept. 2, 1919 1,320,233 Jamerson Oct. 28, 1919 1,359,295 'Immble Nov. 16, 1920 

